Q (16): Assertion : Magnesium ribbon burns with a dazzling white flame and changes into a white powder
Reason : It is formed due to the reaction between magnesium and oxygen present in the air.
(MCQ)
( a ) Both A and R are true and R is the correct explanation of A.
( b ) Both A and R are true but R is not the correct explanation of A.
( c ) A is true but R is false.
( d ) A is false but R is true.
Q (17): Assertion : The total mass of the elements present in the products of a chemical reaction has to be equal to the total mass of the elements present in the reactants.
Reason : Mass can be created and destroyed in a chemical reaction.
(MCQ)
( a ) Both A and R are true and R is the correct explanation of A.
( b ) Both A and R are true but R is not the correct explanation of A.
( c ) A is true but R is false.
( d ) A is false but R is true.
Q (18): A ssertion : Calcium oxide reacts vigorously with water to produce slaked lime (calcium hydroxide) releasing a large amount of heat.
Reason : Such a reaction in which a single product is formed from two or more reactants is known as a combination reaction.
( MCQ)
( a ) Both A and R are true and R is the correct explanation of A.
( b ) Both A and R are true but R is not the correct explanation of A.
( c ) A is true but R is false.
( d ) A is false but R is true.
Q (19): Assertion : The decomposition of vegetable matter into compost is an example of an exothermic reaction
Reason : Large amount of heat is evolved in this reaction.
(MCQ)
( a ) Both A and R are true and R is the correct explanation of A.
( b ) Both A and R are true but R is not the correct explanation of A
( c ) A is true but R is false.
( d ) A is false but R is true.
Q (20): Assertion : During digestion, food is broken down into simpler substances.
Reason : These carbohydrates are broken down to form fat.
(MCQ)
( a ) Both A and R are true and R is the correct explanation of A.
( b ) Both A and R are true but R is not the correct explanation of A.
( c ) A is true but R is false.
( d ) A is false but R is true.

Plzzzzz give me the correct answer​